Receptos, a San Diego-based biotech startup formed by a number of Biogen Idec veterans, has nailed down $25 million in venture capital to develop a vivid new way to look at certain protein structures on cells that it hopes will ultimately take a lot of the guesswork out of drug discovery.

The cash infusion is coming from Venrock Associates, Arch Venture Partners, Flagship Ventures, and Lilly Ventures. Bill Rastetter, a partner at Venrock who was the CEO of Idec Pharmaceuticals before it merged into Cambridge, MA-based Biogen Idec, has joined Receptos as CEO.

The big idea for the fledgling company comes from the labs of Ray Stevens and Hugh Rosen at The Scripps Research Institute in San Diego. The Scripps scientists have developed a process for capturing the first high-resolution crystal structure images of certain spaghetti-like targets on cells, known as G-protein coupled receptors. These are highly complex proteins that snake inside and outside of cells. This architecture, and the lack of great 3-D imaging to see them in their full glory, makes them especially tricky to develop specific drugs against. Even so, an estimated 30 to 40 percent of all pharmaceuticals worldwide hit these GPCR targets, including best-sellers for depression, allergies, and high blood pressure. Because the new method of capturing images of these proteins holds the potential for creating more specific new drugs against these targets, it was called one of the top 10 breakthroughs of the year in 2007 by Science magazine.

“It’s sort of like if you can’t look under the hood of a car, how can you know what’s wrong?” Stevens says. “What Receptos does is enable scientists to see the binding sites on the targets, to develop more effective new drugs against them.” He adds that this has implications far beyond any one drug, that this method will be applied over and over against a number of targets. “The potential is enormous,” Stevens says.

Ray Stevens

Rosen, a co-founder and former Merck executive director, called the new technique a “quantum leap” that will clear the way for more data-driven discovery of new drugs.

This isn’t meant to say any of this will be easy. Part of the challenge with characterizing GPCRs is that scientists using current methods are required to have the natural occurring, or synthetic, ligand that binds with the receptor. Receptos still has to operate within that limitation. But what the company has developed of value is a 15-step, reproducible process to make high-resolution crystal images of the known GPCRs, which gives scientists much more information about the target they are developing drugs against, Stevens says.

Once drug developers have the crystal structure figured out, then they have a solid template to design drugs with the desired ability to turn on or off a certain function related to disease. While this ability to capture crystal structures has eluded scientists looking at GPCRs in the past, it’s a standard part of the toolbox for researchers looking at tyrosine kinases—which have since become one of the hot targets in cancer biology.

So what does Receptos plan to do with this new platform for discovering drugs? A few things. It plans to form partnerships with other drug companies that want this same kind of information at their fingertips, says Marcus Boehm, a co-founder and vice president of chemistry. That will help pay the bills … Next Page »